Question 165·Hard·Inferences
Marine biologists tracking the migratory routes of blue whales once relied chiefly on nineteenth- and twentieth-century ship logs describing seasonal whale sightings. Recently, they have augmented those records with acoustic data collected by underwater microphones attached to transoceanic cables. Preliminary comparisons reveal that, over the past 15 years, whales have gradually shifted their routes to follow new deep-water krill blooms produced by changing ocean currents. The researchers contend that integrating these historical and modern data sets ______
Which choice most logically completes the text?
For logical-completion inference questions, (1) paraphrase the paragraph’s main takeaway, (2) identify what the blank must do (result, implication, purpose), and (3) eliminate options that add unsupported certainty, introduce an unmentioned pattern (like a “cycle”), or change the author’s focus (like replacing one data source instead of integrating both). Choose the option that most directly extends the passage’s logic in a cautious, evidence-based way.
Hints
Stay focused on what “integrating” implies
“Integrating” means using both sources together. Look for an answer that describes a benefit of combining information rather than discarding one source.
Use the 15-year trend appropriately
The passage says the shift happened over the past 15 years, but it does not say the shift repeats every 15 years. Be careful about answers that turn “15 years” into a cycle.
Match the cautious scientific tone
Words like “preliminary comparisons” suggest the researchers are not making absolute claims. Avoid choices that sound final or certain (for example, that changes have stopped).
Prefer the option that extends the passage logically
The passage shows how combining sources reveals a trend and a likely cause. A strong completion will extend that logic to what scientists can do next (for example, improved forecasting).
Step-by-step Explanation
Identify what the blank must do
The final sentence begins, “The researchers contend that integrating these historical and modern data sets ______.” So the blank should state a reasonable benefit or conclusion that follows from combining ship logs (historical) with acoustic data (modern).
Restate the key evidence
Key points from the passage:
- Older ship logs recorded seasonal whale sightings.
- Researchers now add acoustic data from underwater microphones.
- Comparing these sources suggests that, over the last 15 years, whales have gradually shifted routes to follow new krill blooms linked to changing ocean currents.
Predict the kind of claim that fits
Because the passage highlights (1) a trend over time and (2) a likely environmental driver, combining long-term and recent data most naturally supports a cautious, forward-looking claim about improving understanding and prediction—not a claim that one source is obsolete or that changes have definitively ended.
Test each option against the passage
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“shows that blue whales have always changed their routes in predictable 15-year cycles.” The passage mentions changes over the past 15 years, but it does not indicate a repeating cycle.
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“suggests that acoustic recordings can replace ship logs as evidence for blue whale migration in the nineteenth and twentieth centuries.” Acoustic data are described as recent, and the researchers are integrating sources, not replacing the historical record.
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“indicates that the whales’ route shifts have already stabilized and are unlikely to change further.” The passage reports a gradual shift and describes findings as preliminary; it does not claim the shift has ended or stabilized.
The only choice that logically matches the idea of combining sources to improve what scientists can do with the information is the prediction-focused option.
Select the option that best matches the passage’s logic and tone
The choice stating that integration may allow more accurate prediction of future migration changes than either source alone fits the purpose of combining complementary data sets and matches the cautious tone (“preliminary comparisons”). Therefore, the correct answer is:
may allow scientists to predict future changes in whale migration more accurately than either data source could on its own.